The present invention relates to a system, i.e. method and apparatus for monitoring development of medication induced febrile neutropenia. The invention has particular utility in connection with the monitoring of chemotherapy induced febrile neutropenia, and will be described in connection with such utility, although other utilities are contemplated.
Immune dysregulation is a component of many pathological diseases or conditions. Such dysregulation may be a factor that favors the establishment, maintenance or progression of diseases or conditions. Immune response or immune suppression also frequently results from medication treatments including specifically chemotherapy that is used in the treatment of cancer.
Outpatient therapy for low-risk neutropenic patients is considered safe, but remains an uncommon practice. However, even with regular monitoring, including frequent in-office or outpatient monitoring, patients frequently get into trouble resulting in costly hospitalizations for treatment of chemotherapy induced febrile neutropenia, since by the time the patient is diagnosed, it often is too late for treatment other than through administration of parenteral antibiotics.
Although the definition for chemotherapy induced febrile neutropenia vary across institutions and guidelines, most North American Societies define a single oral temperature of >38.3° C. (101.3° F.) or a temperature of >38° C. (100.4° F.) sustained for >1 hour as significant and neutropenia with an ANC<1000 cells/microL, whilst severe neutropenia is considered an absolute neutrophil count (ANC)<500 cells/microL, or an ANC that is expected to decrease to <500 cells/microL over the next 48 hours1. In spite of the wide utilization of growth factors and prophylactic antimicrobial therapy in patients obtaining chemotherapy for their malignant disease, febrile neutropenia still remains a common treatment related complication2. Early studies linked infections in the context of severe neutropenia with a substantial mortality rate3.
The corresponding concern of the development of an overwhelming sepsis episode rendered hospitalization with the administration of parenteral antibiotics as the standard of care in the management of patients with febrile neutropenia for many decades. It is now well recognized that neutropenic fever patients represent a very heterogeneous group4. The Multinational Association for the Supportive Care in Cancer (MASCC) proposed a seven point model, consisting of (1) degree of symptom burden, (2) presence or absence of hypotension, (3) need for IV fluid resuscitation, (4) presence or absence of COPD as a comorbidity, (5) solid tumor malignancy or hematologic malignancy without prior fungal infection, (6) outpatient status and (7) age above or below sixty years old as relevant clinico-demographic cofactors for the risk stratification of patients presenting with chemotherapy induced febrile neutropenia4. At least seven randomized trials have established the use of outpatient antibiotics as a safe and efficacious strategy in low risk febrile neutropenia5-11. In addition, the comparability of oral with intravenous regimens has been demonstrated12-15. Several guidelines support the use of outpatient antibiotics in the low risk setting16-18. A recent systematic review with meta-analysis revealed equal mortality with inpatient versus outpatient therapy with comparables rates of treatment failure2. Benefits of outpatient therapy in this setting include increased patient acceptance and the absence of exposure to a nosocomial environment. In addition, recent health economic comparisons of inpatient versus outpatient therapy in the low risk neutropenic feversetting have demonstrated striking savings with outpatient therapy19,20. 
In spite of the available feasibility data and the benefits of outpatient therapy vs inpatient therapy described above, a large amount of patients with chemotherapy associated neutropenic fever are still admitted to the hospital for parenteral IV antibiotic therapy for the full length of their neutropenic presentation. A major reason for this is concern of further deterioration following the initial assessment at presentation.